#!/bin/bash -e
# Verify the given password hash against a password
if test "$1"
then hash="$1"; shift
else printf "Hash? " && read -r hash
fi
while echo "Type password (no echo) " && read -r -s password && test "$password"; do
param=$(echo "$hash" | cut -d\$ -f3)
# Check if hash contains parameters
if test $(echo "$hash" | tr -cd \$ | wc -c) -gt 3
then salt=$(echo "$hash" | cut -d\$ -f4)
    salted_hash=$(mkpasswd -m sha-512 --"$param" --salt="$salt" "$password")
else salted_hash=$(mkpasswd -m sha-512 --salt="$param" "$password")
fi

# Compare the generated hash with the original hash
if [[ "$salted_hash" == "$hash" ]]
then echo ":) Password correct"; break
else echo "X  Password incorrect"
fi
done